Emulsions having UV sunscreen factors and carnosines

ABSTRACT

The invention relates to emulsions containing (a) at least one UV sunscreen factor, (b) at least one compound of formula (I) where R1 is II or CII 3  and R2 is II or COOII or salts thereof, (c) at least one emulsifier, and optionally (d1) a carrier and/or (d2) an oil body, providing that the emulsions have a droplet size at which the D50 value ranges from 0.1 to 100 μm.

FIELD OF THE INVENTION

The invention lies in the field of cosmetics and relates especially to sunscreen agents in emulsion form having improved storage stability.

PRIOR ART

According to a statistic from 2015, the number of people over the age of 14 in Germany who apply sunscreen products on more than 20 days in the year is approximately 20 million and has been increasing constantly over recent years. Sunscreen agents are thus among the cosmetic products that are most in demand, especially since, according to current studies, the number of skin cancers caused by UV radiation has more than doubled since 2003.

Sunscreen agents differ greatly in terms of composition, quality and thus ultimately also in terms of price. Simple formulations, which are offered primarily by discounters, are of simple composition and contain only a small number of sun protection factors in small amounts, which at most results in short-term protection on pre-tanned skin. Other products contain a “cocktail” of sun protection factors, that is to say they make use of the fact that sun protection factors have their absorption maximum at different wavelength ranges and thus, when chosen intelligently, uniform protection over a broad spectrum of white sunlight is achieved. It is obvious that such products are not only of higher quality but are also more expensive for the consumer.

The trend to improve the action of cosmetic agents by adding further active ingredients continues unabated. In the field of sunscreen products, for example, there is great interest in identifying active ingredients which extend the scope of protection, that is to say to provide protection not only against light-induced skin damage or skin ageing (UV influence) but also against other influences, such as, for example, environmental toxins. The fact is that sun protection factors are largely or even completely useless against environmentally induced damage to the skin, since such damage follows completely different reaction pathways in the cell.

The introduction of new or additional active ingredients is not only associated with an increase in quality however; the problems also increase. Not every active ingredient can be incorporated into any desired formulation; the complexity of production and storage increases, and in some cases it must also be considered that the additive itself is sensitive to the influence of air or light.

Of particular interest are corresponding preparations in emulsion form, in which the droplets have a particularly small diameter, since they can not only be readily atomized but also have a high spreadability, that is to say rapidly penetrate the skin. Such emulsions are distinguished by the fact that the droplets are so small that they do not scatter light. The solutions therefore appear transparent. The disadvantage of such formulations, however, is that they do not have sufficient stability on prolonged storage and in particular at high temperatures and demix as easily as they formed. However, it is precisely such conditions that sunscreen agents are routinely subjected to.

In principle this is harmless for the product, since it can be homogenized again by repeated vigorous shaking. For a consumer, however, who has specifically decided on a high-quality and correspondingly expensive product, this is unsatisfactory and may lead to his next purchase decision having a different outcome.

The object of the present was therefore to provide emulsion-based sunscreen agents which are sufficiently stable even when stored at elevated temperature for a prolonged period. Part of this object was to find corresponding stabilizers which, where possible, not only fulfill a functional purpose but additionally also have an active ingredient character which is advantageous for the field of use of sun protection.

DESCRIPTION OF THE INVENTION

The invention firstly provides emulsions comprising

(a) at least one UV sun protection factor,

(b) at least one compound of formula (I)

wherein R1 represents H or CH₃ and R2 represents H or COOH, or salts thereof;

(c) at least one emulsifier, and optionally

(d1) carriers and/or

(d2) oily substances,

with the proviso that the emulsions have a droplet size in which the D50 value is in the range from 0.1 to 100 μm, in particular in the range from 0.5 to 70 μm and particularly preferably in the range from 1 to 50 μm.

The figure means that at least 50% of all the emulsion droplets lie within the indicated range of values. It is further preferred that the D90 value is in the range from in the range from 1 to 150 μm and particularly preferably in the range from 10 to 100 μm. It is particularly preferred that both the D50 value and the D90 value are in the range from 0.1 to 100 μm and in particular in the range from 1 to 40 μm.

The emulsions can be in the form of O/W or W/O emulsions or in the form of multiple W/O/W or O/W/O emulsions.

With the carnosines, a group of substances has, surprisingly, been found which not only have partly known and partly hitherto unknown active ingredient properties in connection with protecting the skin against light- and environment-induced damage, but are also capable of keeping emulsions based on UV-A and/or UV-B sun protection factors stable even at high temperatures and over prolonged periods. Carnosines thus fulfill the profile of requirements described at the beginning perfectly, in that they impart to the formulations an active ingredient effect and at the same time also fulfill a functional purpose, namely act as a stabilizer.

UV Sun Protection Factors

UV sun protection factors (component a) are to be understood as being, for example, organic substances (sun protection filters) which are in liquid or crystalline form at room temperature and which are capable of absorbing ultraviolet rays and giving off the absorbed energy again in the form of long-wave radiation, for example heat. The UV sun protection factors are conventionally present, each considered on its own, in amounts of from 0.1 to 5% by weight and preferably from 0.2 to 1% by weight. The total amount of sun protection factors in a preparation can, however, be significantly higher and, depending on the SPF (sun protection factor), can be up to 25% by weight, preferably from approximately 10 to approximately 15% by weight.

UVB filters can be oil-soluble or water-soluble. There may be mentioned as oil-soluble substances, for example:

-   -   3-benzylidene camphor or 3-benzylidene norcamphor and         derivatives thereof, for example 3-(4-methylbenzylidene) camphor         described;     -   4-aminobenzoic acid derivatives, preferably         4-(dimethylamino)benzoic acid 2-ethylhexyl ester,         4-(dimethylamino)benzoic acid 2-octyl ester and         4-(dimethylamino)benzoic acid amyl ester;     -   esters of cinnamic acid, preferably 4-methoxycinnamic acid         2-ethylhexyl ester, 4-methoxycinnamic acid propyl ester,         4-methoxycinnamic acid isoamyl ester, 2-cyano-3,3-phenylcinnamic         acid 2-ethylhexyl ester (octocrylene);     -   esters of salicylic acid, preferably salicylic acid 2-ethylhexyl         ester, salicylic acid 4-isopropylbenzyl ester, salicylic acid         homomenthyl ester;     -   derivatives of benzophenone, preferably         2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4′-methyl         benzophenone, 2,2′-dihydroxy-4-methoxybenzophenone;     -   esters of benzalmalonic acid, preferably 4-methoxybenzmalonic         acid di-2-ethylhexyl ester;     -   triazine derivatives, such as, for example,         2,4,6-trianilino-(p-carbo-2′-ethyl-1′-hexyloxy)-1,3,5-triazine         and octyl triazone or dioctyl butamido triazone (Uvasorb® HEB);     -   propane-1,3-diones, such as, for example         1-(4-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione;     -   ketotricyclo(5.2.1.0)decane derivatives.

There are suitable as water-soluble substances:

-   -   2-phenylbenzimidazole-5-sulfonic acid and the alkali, alkaline         earth, ammonium, alkylammonium, alkanolammonium and glucammonium         salts thereof;     -   1H-benzimidazole-4,6-disulfonic acid, 2,2′-(1,4-phenylene)bis-,         disodium salt (Neo Heliopan® AP);     -   sulfonic acid derivatives of benzophenones, preferably         2-hydroxy-4-methoxybenzo-phenone-5-sulfonic acid and its salts;     -   sulfonic acid derivatives of 3-benzylidene camphor, such as, for         example, 4-(2-oxo-3-bornylidenemethyl)benzene sulfonic acid and         2-methyl-5-(2-oxo-3-bornylidene)sulfonic acid and salts thereof.

As typical UV-A filters there are suitable in particular derivatives of benzoyl methane, such as, for example, 1-(4′-tert.butylphenyl)-3-(4′-methoxyphenyl)propane-1,3-dione, 4-tert.-butyl-4′-methoxy-dibenzoylmethane (Parsol® 1789), 2-(4-diethylamino-2-hydroxybenzoyl)-benzoic acid hexyl ester (Uvinul® A Plus), 1-phenyl-3-(4′-isopropylphenyl)-propane-1,3-dione, as well as enamine compounds. The UV-A and UV-B filters can of course also be used in mixtures. Particularly advantageous combinations consist of the derivatives of benzoylmethane, for example 4-tert.-butyl-4′-methoxydibenzoyl methane (Parsol® 1789) and 2-cyano-3,3-phenylcinnamic acid 2-ethylhexyl ester (octocrylene) in combination with esters of cinnamic acid, preferably 4-methoxycinnamic acid 2-ethylhexyl ester and/or 4-methoxycinnamic acid propyl ester and/or 4-methoxycinnamic acid isoamyl ester. Such combinations are advantageously combined with water-soluble filters such as, for example, 2-phenylbenzimidazole-5-sulfonic acid and the alkali, alkaline earth, ammonium, alkylammonium, alkanolammonium and glucammonium salts thereof.

Carnosines

The carnosines, which are represented by formula (I) and form component (b), are compounds which are known in principle and which are accessible by conventional processes of organic chemistry. Preference is thereby given to the group of substances formed by carnosine, L-carnosine, D-carnosine, D/L-carnosine, carnitine, carnitine*HCLanserine, D-anserine, L-anserine and L-anserine*HNO₃ and mixtures thereof.

According to the invention, salts of the compounds of formula (I) are preferably understood as being salts of the compounds of formula (I) with mineral acids, particularly preferably salts of formula (II):

wherein n represents 1, 2 or 3 and A represents HCl or HNO₃ and R1 represents H or CH₃ and R2 represents H or COOH.

The advantageous use of carnosines in the field of the prophylaxis of light-induced skin ageing or skin damage is well known from the prior art.

For example, it is known from a study by Aruoma et al. from 1989 that carnosine is capable of capturing ROS (reactive oxygen species) [Biochem. J. 264(3), p. 863-869 (1989)]. According to a report by Babizhayev et al., carnosine is additionally able to capture alpha-beta-unsaturated aldehydes, which are liberated in the peroxidation of fatty acids of the cell membrane under oxidative stress [Membran & Cell Biol. 12(1), p. 89-99 (1998)].

EP 1310238 A2 (BASF) discloses cosmetic or dermatological sun protection agent preparations which comprise at least one cholesteric liquid-crystalline component which reflects in the infrared wavelength range of from 750 nm to 2500 nm, at least one filter substance which protects against radiation in the ultraviolet ray range of from 280 nm to 449 nm, and at least one cosmetically acceptable carrier, and the use thereof. Further antioxidants, such as, for example, carnosine, can additionally be present.

EP 1388339 A1 (VISA) discloses the use of carnosine for controlling the ageing process by reversing, preventing and reducing wrinkle formation of the skin. Carnosine is described as an anti-wrinkle active ingredient which inter alia also protects against glycosylation and chronic inflammation.

EP 2181697 A2 (SHISEIDO) provides sunscreen agents in O/W form which are distinguished by a special cocktail of emulsifiers and sun protection filters. Table 3-3 discloses two compositions (Examples 22 and 23) which contain the combination of carnosine with UV filters.

In addition, there are known from EP 1591105 A1 (STADA) cosmetic and pharmaceutical preparations comprising an antioxidant, which preparations protect the skin against IR radiation. Among the many possible antioxidants, carnosine and arnesine are also mentioned. The compositions, which are to be administered topically, further comprise one or more inorganic and/or organic UV filters. That specification does not contain a specific disclosure of mixtures of carnosines and UV filters.

EP 2545898 A1 (COTY) discloses preparations which protect the skin against damage by IR radiation and thereby comprise plant extracts, vitamins, ruby powder, mica and titanium dioxide. In paragraph [0026], carnosine is also mentioned as a further suitable auxiliary substance, but as a radical acceptor. That specification also does not contain a specific disclosure of mixtures of carnosines and UV filters.

International patent application WO 1990 006102 A1 (PEPTIDE TECHNOLOGY) likewise relates to the antioxidative property of carnosine compounds. It is mainly disclosed that the compounds found reduce or prevent collagen crosslinking in the skin and/or damage to skin cell DNA, in particular caused by ageing or UV radiation. Administration is carried out topically or by injection. There is no mention in the specification of a mixture with UV filters.

WO 2010 124817 A2 (KPSS) relates to conditioning compositions for hair based, inter alia, on dipeptides such as, for example, carnosine. In the implementation examples there is a disclosure of the combination of carnosine with a UV filter, namely benzophenone-3, in Examples 4, 8, 9 and 16, wherein the weight ratio between carnosine and benzophenone-3 is in the range from 1:03 to 1:2.

Reference is further made to international patent application WO 2014 128228 A2 (SYMRISE), which reveals the suitability of these substances for protecting against IR radiation on the basis of the inhibition of MMP expression. Specifically, mixtures of equal amounts by weight of carnosine with Uvinul A and octocrylene are disclosed therein.

US 2006/216251 A1 (TRACIE MARTIN) provides topical compositions comprising carnosine, carnitine and a lipoic acid for the treatment and protection of the skin, in particular as regards signs of skin ageing in relation to chrono-ageing or photo-ageing, which is directed at wrinkles, sagging skin and loss of elasticity. Treatment directed at hyperpigmentation is likewise disclosed. In the specification, reference is likewise made to the influence of carnosines on MMP-1 inhibition. Examples 1 to 8 disclose an amount of carnosine used in the range 1% by weight and 2% by weight.

According to the English-language abstract of KR 2004 0074795 A (A E KYUNG), from 0.1 to 2% by weight carnosine in cosmetic compositions has an antioxidative effect on the skin and increases collagen synthesis. A formulation comprising 0.1% by weight carcinine (carnosine), 0.5% by weight salicylic acid, 5.0% by weight 1,3-butylene glycol, 1.3% by weight polyethylene sorbitan monolaurate, 0.7% by weight polyethylene lauryl ether, 15% by weight ethanol, 0.2% by weight fragrances, preservatives and water is given as an example.

The applicant has additionally found that carnosine in particular increases the activity of G6PDH production and counteracts apoptosis. The use of the substances as protective and constructive medicaments or care products is possible in principle for all preparations which are used for prevention against damage or in the case of damage to the skin and thus in skin care and prophylaxis. Another use in this field is application to sensitive skin damaged by allergy or other causes. Damage to the skin can thereby have very different causes.

The amount of carnosines conventionally used, based on the emulsion, is typically from approximately 0.001 to approximately 2.5% by weight, preferably approximately from 0.005 to 2% by weight and in particular from approximately 0.01 to approximately 1.5% by weight.

Emulsifiers

There are suitable as emulsifiers for the emulsions, for example, non-ionic surfactants from at least one of the following groups:

-   -   addition products of from 2 to 30 mol of ethylene oxide and/or         from 0 to 5 mol of propylene oxide with linear fatty alcohols         having from 8 to 22 carbon atoms, with fatty acids having from         12 to 22 carbon atoms, with alkylphenols having from 8 to 15         carbon atoms in the alkyl group, as well as alkylamines having         from 8 to 22 carbon atoms in the alkyl moiety;     -   alkyl and/or alkenyl oligoglycosides having from 8 to 22 carbon         atoms in the alk(en)yl moiety, and ethoxylated analogs thereof;     -   addition products of from 1 to 15 mol of ethylene oxide with         castor oil and/or hardened castor oil;     -   addition products of from 15 to 60 mol of ethylene oxide with         castor oil and/or hardened castor oil;     -   partial esters of glycerol and/or sorbitan with unsaturated,         linear or saturated, branched fatty acids having from 12 to 22         carbon atoms and/or hydroxycarboxylic acids having from 3 to 18         carbon atoms, as well as adducts thereof with from 1 to 30 mol         of ethylene oxide;     -   partial esters of polyglycerol (average inherent degree of         condensation 2 to 8), polyethylene glycol (molecular weight 400         to 5000), trimethylolpropane, pentaerythritol, sugar alcohols         (e.g. sorbitol), alkyl glucosides (e.g. methyl glucoside, butyl         glucoside, lauryl glucoside) as well as polyglucosides (e.g.         cellulose) with saturated and/or unsaturated, linear or branched         fatty acids having from 12 to 22 carbon atoms and/or         hydroxycarboxylic acids having from 3 to 18 carbon atoms, as         well as adducts thereof with from 1 to 30 mol of ethylene oxide;     -   mixed esters of pentaerythritol, fatty acids, citric acid and         fatty alcohol and/or mixed esters of fatty acids having from 6         to 22 carbon atoms, methylglucose and polyols, preferably         glycerol or polyglycerol;     -   mono-, di- and tri-alkyl phosphates as well as mono-, di- and/or         tri-PEG-alkyl phosphates and salts thereof;     -   wool wax alcohols;     -   polysiloxane-polyalkyl-polyether copolymers or corresponding         derivatives;     -   block copolymers, for example polyethylene glycol-30         dipolyhydroxystearate;     -   polymeric emulsifiers, for example Pemulen types (TR-1, TR-2)         from Goodrich or Cosmedia® SP from Cognis;     -   polyalkylene glycols; and     -   glycerol carbonate.

Particularly suitable emulsifiers are discussed in greater detail hereinbelow:

Alkoxylates. The addition products of ethylene oxide and/or propylene oxide with fatty alcohols, fatty acids, alkylphenols or with castor oil are known products which are available commercially. They are homolog mixtures whose mean degree of alkoxylation corresponds to the ratio of the amounts of ethylene oxide and/or propylene oxide and substrate with which the addition reaction is carried out. C_(12/18)-Fatty acid mono- and di-esters of addition products of ethylene oxide with glycerol are known as refatting agents for cosmetic preparations.

Alkyl and/or alkenyl oligoglycoside. Alkyl and/or alkenyl oligoglycosides, their preparation and their use are known from the prior art. They are prepared in particular by reaction of glucose or oligosaccharides with primary alcohols having from 8 to 18 carbon atoms. With regard to the glycoside radical, both monoglycosides, in which a cyclic sugar residue is glycosidically bonded to the fatty alcohol, and oligomeric glycosides having a degree of oligomerization up to preferably approximately 8 are suitable. The degree of oligomerization is a statistical mean based on a conventional homolog distribution for such commercial products.

Partial glycerides. Typical examples of suitable partial glycerides are hydroxystearic acid monoglyceride, hydroxystearic acid diglyceride, isostearic acid monoglyceride, isostearic acid diglyceride, oleic acid monoglyceride, oleic acid diglyceride, ricinoleic acid monoglyceride, ricinoleic acid diglyceride, linoleic acid monoglyceride, linoleic acid diglyceride, linolenic acid monoglyceride, linolenic acid diglyceride, erucic acid monoglyceride, erucic acid diglyceride, tartaric acid monoglyceride, tartaric acid diglyceride, citric acid monoglyceride, citric diglyceride, malic acid monoglyceride, malic acid diglyceride and commercial mixtures thereof which, subordinately from the preparation process, may still contain small amounts of triglyceride. Also suitable are addition products of from 1 to 30 mol, preferably from 5 to 10 mol, of ethylene oxide with the mentioned partial glycerides.

Sorbitan esters. There come as sorbitan esters sorbitan monoisostearate, sorbitan sesquiisostearate, sorbitan diisostearate, sorbitan triisostearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan dioleate, sorbitan trioleate, sorbitan monoerucate, sorbitan sesquierucate, sorbitan dierucate, sorbitan trierucate, sorbitan monoricinoleate, sorbitan sesquiricinoleate, sorbitan diricinoleate, sorbitan triricinoleate, sorbitan mono-hydroxystearate, sorbitan sesquihydroxystearate, sorbitan dihydroxystearate, sorbitan trihydroxystearate, sorbitan monotartrate, sorbitan sesquitartrate, sorbitan ditartrate, sorbitan tritartrate, sorbitan monocitrate, sorbitan sesquicitrate, sorbitan dicitrate, sorbitan tricitrate, sorbitan monomaleate, sorbitan sesquimaleate, sorbitan dimaleate, sorbitan tri-maleate and commercial mixtures thereof. Also suitable are addition products of from 1 to 30 mol, preferably from 5 to 10 mol, of ethylene oxide with the mentioned sorbitan esters.

Polyglycerol esters. Typical examples of suitable polyglycerol esters are polyglyceryl-2 dipolyhydroxy stearate (Dehymuls® PGPH), polyglycerol-3 diisostearate (Lameform® TGI), polyglyceryl-4 isostearate (Isolan® GI 34), polyglyceryl-3 oleate, diisostearoyl polyglyceryl-3 diisostearate (Isolan® PDI), polyglyceryl-3 methylglucose distearate (Tego Care® 450), polyglyceryl-3 beeswax (Cera Bellina®), polyglyceryl-4 caprate (Polyglycerol Caprate T2010/90), polyglyceryl-3 cetyl ether (Chimexane® NL), polyglyceryl-3 distearate (Cremophor® GS 32) and polyglyceryl polyricinoleate (Admul® WOL 1403) polyglyceryl dimerate isostearate and mixtures thereof. Examples of further suitable polyol esters are the mono-, di- and tri-esters, optionally reacted with from 1 to 30 mol of ethylene oxide, of trimethylolpropane or pentaerythritol with lauric acid, coconut fatty acid, tallow fatty acid, palmitic acid, stearic acid, oleic acid, behenic acid and the like.

Anionic emulsifiers. Typical anionic emulsifiers are aliphatic fatty acids having from 12 to 22 carbon atoms, such as, for example, palmitic acid, stearic acid or behenic acid, as well as dicarboxylic acids having from 12 to 22 carbon atoms, such as, for example, azelaic acid or sebacic acid.

Amphoteric and cationic emulsifiers. Zwitterionic surfactants can further be used as emulsifiers. Zwitterionic surfactants denotes those surface-active compounds that carry at least one quaternary ammonium group and at least one carboxylate group and one sulfonate group in the molecule. Particularly suitable zwitterionic surfactants are the so-called betaines such as the N-alkyl N,N-dimethylammoniumglycinates, for example coco alkyldimethylammoniumglycinate, N-acylaminopropyl N,N-dimethylammoniumglycinate, for example coco acylaminopropyl dimethylammoniumglycinate, and 2-alkyl-3-carboxylmethyl-3-hydroxyethylimidazolines each having from 8 to 18 carbon atoms in the alkyl or acyl group, as well as coco acylaminoethyl hydroxyethyl carboxymethyl glycinate. Particular preference is given to the fatty acid amide derivative known by the CTFA name Cocamidopropyl Betaine. Ampholytic surfactants are likewise suitable emulsifiers. Ampholytic surfactants are understood as being those surface-active compounds that contain in the molecule, in addition to a C_(8/18)-alkyl or -acyl group, at least one free amino group and at least one —COOH or —SO₃H group and are capable of forming internal salts. Examples of suitable ampholytic surfactants are N-alkylglycines, N-alkylpropionic acids, N-alkylaminobutyric acids, N-alkyliminodipropionic acids, N-hydroxyethyl-N-alkylamidopropylglycine, N-alkyltaurines, N-alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acids each having approximately from 8 to 18 carbon atoms in the alkyl group. Particularly preferred ampholytic surfactants are N-coco alkylaminopropionate, coco acylaminoethylamino propionate and C_(12/18)-acylsarcosine. Finally, cationic surfactants also come into consideration as emulsifiers, whereby those of the esterquat type, especially methyl-quaternized di-fatty acid triethanolamine ester salts, are particularly preferred.

In many cases it has been found to be advantageous to use combinations of different emulsifiers, namely binary mixtures (e.g. alkyl polyglucoside/fatty alcohol ethoxylate) or ternary mixtures (e.g. alkyl polyglucoside/alkyl benzenesulfonate/esterquat or mono-glyceride/fatty alcohol ethoxylate/fatty alcohol).

The amount of emulsifiers used can be between approximately 1 and approximately 30% by weight. Preference is given to ranges of approximately from 2 to 20% by weight and in particular approximately from 5 to 10% by weight. Correspondingly preferred combinations are to be found in the implementation examples.

Carriers

Both the emulsions can comprise as an optional component (d1) carriers, or solvents, selected from the group formed by water, alcohols, esters, butylene glycol, dipropylene glycol, ethanol, ethoxydiglycol, ethyl acetate, glycerol, propanol, isopropanol, macrogols, polypropylene glycol(2) methyl ether, polypropylene glycol(3) methyl ether, propylene carbonate, propylene glycol, triethylene glycol, isoparaffin, amyl acetate, amyl benzoate, benzyl acetate, butyl acetate, butylene glycol, butyl lactate, butooctyl benzoate, butooctyl salicylate, C10-C13 alkanes, C14-C17 alkanes, C11-C15 cycloalkanes, caprylyl butyrate, isoparaffins, diacetin, triacetin, dicaprylyl ether, dicaprylyl maleate and mixtures thereof.

The amount of carriers in the emulsion can be up to 50% by weight and is conventionally in the range from approximately 5 to approximately 25% by weight and in particular from approximately 10 to approximately 15% by weight.

Oily Substances

The emulsions can further comprise oily substances (component d2). There come into consideration, for example, Guerbet alcohols based on fatty alcohols having from 6 to 18, preferably from 8 to 10, carbon atoms, esters of linear C₆-C₂₂-fatty acids with linear or branched C₆-C₂₂-fatty alcohols or esters of branched C₆-C₁₃-carboxylic acids with linear or branched C₆-C₂₂-fatty alcohols, such as, for example, myristyl myristate, myristyl palmitate, myristyl stearate, myristyl isostearate, myristyl oleate, myristyl behenate, myristyl erucate, cetyl myristate, cetyl palmitate, cetyl stearate, cetyl isostearate, cetyl oleate, cetyl behenate, cetyl erucate, stearyl myristate, stearyl palmitate, stearyl stearate, stearyl isostearate, stearyl oleate, stearyl behenate, stearyl erucate, isostearyl myristate, isostearyl pa Imitate, isostearyl stearate, isostearyl isostearate, isostearyl oleate, isostearyl behenate, isostearyl oleate, oleyl myristate, oleyl palmitate, oleyl stearate, oleyl isostearate, oleyl oleate, oleyl behenate, oleyl erucate, behenyl myristate, behenyl palmitate, behenyl stearate, behenyl isostearate, behenyl oleate, behenyl behenate, behenyl erucate, erucyl myristate, erucyl palmitate, erucyl stearate, erucyl isostearate, erucyl oleate, erucyl behenate and erucyl erucate. Also suitable are esters of linear C₆-C₂₂-fatty acids with branched alcohols, in particular 2-ethylhexanol, esters of C₁₈-C₃₈-alkylhydroxycarboxylic acids with linear or branched C₆-C₂₂-fatty alcohols, in particular dioctyl malate, esters of linear and/or branched fatty acids with polyhydric alcohols (such as, for example, propylene glycol, dimerdiol or trimertriol) and/or Guerbet alcohols, triglycerides based on C₆-C₁₀-fatty acids, liquid mono-/di-/tri-glyceride mixtures based on C₆-C₁₈-fatty acids, esters of C₆-C₂₂-fatty alcohols and/or Guerbet alcohols with aromatic carboxylic acids, in particular benzoic acid, esters of C₂-C₁₂-dicarboxylic acids with linear or branched alcohols having from 1 to 22 carbon atoms or polyols having from 2 to 10 carbon atoms and from 2 to 6 hydroxyl groups, vegetable oils, branched primary alcohols, substituted cyclohexanes, linear and branched C₆-C₂₂-fatty alcohol carbonates, such as, for example, dicaprylyl carbonate (Cetiol® CC), Guerbet carbonates based on fatty alcohols having from 6 to 18, preferably from 8 to 10, carbon atoms, esters of benzoic acid with linear and/or branched C₆-C₂₂-alcohols (e.g. Finsolv® TN), linear or branched, symmetrical or unsymmetrical dialkyl ethers having from 6 to 22 carbon atoms per alkyl group, such as, for example, dicaprylyl ether (Cetiol® OE), ring-opening products of epoxidized fatty acids with polyols, silicone oils (cyclomethicone, silicon methicone types inter alia) and/or aliphatic or naphthenic hydrocarbons, such as, for example, squalane, squalene or dialkylcyclohexanes.

The amount of oily substances in the emulsion can be up to 50% by weight and is conventionally in the range from approximately 5 to approximately 25% by weight, in particular from approximately 10 to approximately 15 weight.

Further Auxiliary Substances and Additives

The emulsions according to the invention can comprise further typical auxiliary substances and additives, such as, for example, mild surfactants, pearlescent waxes, consistency regulators, thickeners, superfatting agents, stabilizers, polymers, silicone compounds, fats, waxes, lecithins, phospholipids, UV sun protection factors, humectants, biogenic active ingredients, antioxidants, deodorants, antiperspirants, insect repellents, self-tanning agents, tyrosine inhibitors (depigmenting agents), hydrotropes, solubilizers, preservatives, perfume oils, dyes and the like.

Surfactants

Anionic, non-ionic, cationic and/or amphoteric or zwitterionic surfactants can be present as surface-active substances; the description of these substances overlaps with that of the emulsifiers, since they both have surface-active properties.

Typical examples of anionic surfactants are soaps, alkyl benzenesulfonates, alkane sulfonates, olefin sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, α-methyl ester sulfonates, sulfo fatty acids, alkyl sulfates, alkyl ether sulfates, glycerol ether sulfates, fatty acid ether sulfates, hydroxy mixed ether sulfates, monoglyceride (ether) sulfates, fatty acid amide (ether) sulfates, mono- and di-alkyl sulfosuccinates, mono- and di-alkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids and salts thereof, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, N-acylamino acids, such as, for example, acyl lactylates, acyl tartrates, acyl glutamates and acyl aspartates, alkyloligoglucoside sulfates, protein fatty acid condensates (in particular wheat-based plant products), and alkyl (ether) phosphates. If the anionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably narrow, homolog distribution. Typical examples of non-ionic surfactants are fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol ethers, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, mixed ethers or mixed formals, optionally partially oxidized alk(en)yl oligoglycosides or glucoronic acid derivatives, fatty acid N-alkylglucamides, protein hydrolyzates (in particular wheat-based plant products), polyol fatty acid esters, sugar esters, sorbitan esters, polysorbates and amine oxides. If the non-ionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably narrow, homolog distribution. Typical examples of cationic surfactants are quaternary ammonium compounds, such as, for example, dimethyldistearylammonium chloride, and esterquats, in particular quaternized fatty acid trialkanolamine ester salts. Typical examples of amphoteric or zwitterionic surfactants are alkylbetaines, alkylamidobetaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines. The mentioned surfactants are all known compounds. Typical examples of particularly suitable mild surfactants, that is to say surfactants that are particularly well tolerated by the skin, are fatty alcohol polyglycol ether sulfates, monoglyceride sulfates, mono- and/or di-alkyl sulfosuccinates, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, fatty acid glutamates, α-olefin sulfonates, ether carboxylic acids, alkyl oligoglucosides, fatty acid glucamides, alkylamidobetaines, amphoacetals and/or protein fatty acid condensates, the latter preferably based on wheat proteins.

Fats and Waxes

Typical examples of fats are glycerides, that is to say solid or liquid vegetable or animal products which consist substantially of mixed glycerol esters of higher fatty acids, as waxes there are suitable inter alia natural waxes, such as, for example, candelilla wax, carnauba wax, Japan wax, esparto wax, cork wax, guaruma wax, rice germ oil wax, sugarcane wax, ouricury wax, montan wax, beeswax, shellac wax, sperm whale oil, lanolin (wool wax), preen oil, ceresin, ozokerite (earth wax), petrolatum, paraffin waxes, microwaxes; chemically modified waxes (hard waxes), such as, for example, montan ester waxes, Sasol waxes, hydrogenated jojoba waxes as well as synthetic waxes, such as, for example, polyalkylene waxes and polyethylene glycol waxes. In addition to the fats, fat-like substances, such as lecithins and phospholipids, are also suitable as additives. The person skilled in the art will understand the term lecithins as meaning those glycero-phospholipids which are formed from fatty acids, glycerol, phosphoric acid and choline by esterification. Lecithins are therefore frequently also among experts as phosphatidylcholines (PC). There may be mentioned as examples of natural lecithins the cephalins, which are also referred to as phosphatidic acids and are derivatives of 1,2-diacyl-sn-glycerol-3-phosphoric acids. By contrast, phospholipids are usually understood as being mono- and preferably di-esters of phosphoric acid with glycerol (glycerol phosphates), which are generally included among the fats. In addition, sphingosines or sphingolipids are also suitable.

Pearlescent Waxes

There are suitable as pearlescent waxes, for example: alkylene glycol esters, especially ethylene glycol distearate; fatty acid alkanolamides, especially coconut fatty acid diethanolamide; partial glycerides, especially stearic acid monoglyceride; esters of polyvalent, optionally hydroxy-substituted carboxylic acids with fatty alcohols having from 6 to 22 carbon atoms, especially long-chain esters of tartaric acid; fatty substances, such as, for example, fatty alcohols, fatty ketones, fatty aldehydes, fatty ethers and fatty carbonates, which contain at least 24 carbon atoms in total, especially laurone and distearyl ether; fatty acids such as stearic acid, hydroxystearic acid or behenic acid, ring-opening products of olefin epoxides having from 12 to 22 carbon atoms with fatty alcohols having from 12 to 22 carbon atoms and/or polyols having from 2 to 15 carbon atoms and from 2 to 10 hydroxyl groups, and mixtures thereof.

Cooling Substances

Cooling substances are compounds which produce a sensation of coolness on the skin. Generally, such substances are menthol compounds which—in addition to the menthol basic structure itself—for example selected from the group formed by menthol methyl ether, menthone glyceryl acetal (FEMA GRAS¹ 3807), menthone glyceryl ketal (FEMA GRAS 3808), menthyl lactate (FEMA GRAS 3748), menthol ethylene glycol carbonate (FEMA GRAS 3805), menthol propylene glycol carbonate (FEMA GRAS 3806), menthyl-N-ethyloxamate, monomethyl succinate (FEMA GRAS 3810), monomenthyl glutamate (FEMA GRAS 4006), menthoxy-1,2-propanediol (FEMA GRAS 3784), menthoxy-2-methyl-1,2-propanediol (FEMA GRAS 3849) and also the menthanecarboxylic acid esters and amides WS-3, WS-4, WS-5, WS-12, WS-14 and WS-30 and mixtures thereof. ¹FEMA stands for “Flavor and Extracts Manufacturers Association” and GRAS is defined as “Generally Regarded As Safe”. A FEMA GRAS designation means tha the substance so characterized is tested according to a standard method and is considered toxicologically harmless.

A first important representative of these substances is monomenthyl succinate (FEMA GRAS 3810). Both the succinate and the analogous monomenthyl glutarate (FEMA GRAS 4006) are important representatives of monomenthyl esters based on di- and poly-carboxylic acids:

Examples of applications of these substances are to be found, for example, in publications WO 2003 043431 (Unilever) or EP 1332772 A1 (IFF).

The next important group of menthol compounds which are preferred within the meaning of the invention comprises carbonate esters of menthol and polyols, such as, for example, glycols, glycerol or carbohydrates, such as, for example, menthol ethylene glycol carbonate (FEMA GRAS 3805=Frescolat® MGC), menthol propylene glycol carbonate (FEMA GRAS 3784=Frescolat® MPC), menthol 2-methyl-1,2-propanediol carbonate (FEMA GRAS 3849) or the corresponding sugar derivatives. Likewise preferred are the menthol compounds menthyl lactate (FEMA GRAS 3748=Frescolat® ML) and in particular menthone glyceryl acetal (FEMA GRAS 3807) or menthone glyceryl ketal (FEMA GRAS 3808), which is marketed under the name Frescolat® MGA. Among these substances, menthone glyceryl acetal/ketal and menthyl lactate as well as menthol ethylene glycol carbonate or menthol propylene glycol carbonate, which are marketed by the applicant under the names Frescolat® MGA, Frescolat® ML, Frecolat® MGC and Frescolat® MPC, have been found to be most particularly advantageous.

In the 70s of the last century, menthol compounds having a C—C bond in the 3-position were developed for the first time, and a number of representatives of these compounds can likewise be used. These substances are referred to generally as WS types. The basic structure is a menthol derivative in which the hydroxyl group has been replaced by a carboxyl group (WS-1). All further WS types, such as, for example, the preferred species WS-3, WS-4, WS-5, WS-12, WS-14 and WS-30, are derived from that structure.

Consistency Regulators and Thickeners

There come into consideration as consistency regulators primarily fatty alcohols or hydroxy fatty alcohols having from 12 to 22 and preferably from 16 to 18 carbon atoms and, in addition, partial glycerides, fatty acids or hydroxy fatty acids. Preference is given to a combination of these substances with alkyl oligoglucosides and/or fatty acid N-methylglucamides of equal chain length and/or polyglycerol poly-12-hydroxystearates. Suitable thickeners are, for example, Aerosil types (hydrophilic silicas), polysaccharides, in particular xanthan gum, guar-guar, agar-agar, alginates and tyloses, carboxymethylcellulose and hydroxyethyl- and hydroxypropyl-cellulose, also higher molecular weight polyethylene glycol mono- and di-esters of fatty acids, polyacrylates (e.g. Carbopols® and Pemulen types from Goodrich; Synthalens® from Sigma; Keltrol types from Kelco; Sepigel types from Seppic; Salcare types from Allied Colloids), polyacrylamides, polymers, polyvinyl alcohol and polyvinylpyrrolidone. Bentonites, such as, for example, Bentone® Gel VS-5PC (Rheox), which is a mixture of cyclopentasiloxane, disteardimonium hectorite and propylene carbonate, have also been found to be particularly effective. There are also suitable surfactants, such as, for example, ethoxylated fatty acid glycerides, esters of fatty acids with polyols such as, for example, pentaerythritol or trimethylolpropane, fatty alcohol ethoxylates with narrow homolog distribution or alkyl oligoglucosides, as well as electrolytes such as sodium chloride and ammonium chloride.

Superfatting Agents and Stabilizers

As superfatting agents there can be used substances such as, for example, lanolin and lecithin as well as polyethoxylated or acylated lanolin and lecithin derivatives, polyol fatty acid esters, monoglycerides and fatty acid alkanolamides, whereby the latter at the same time serve as foam stabilizers.

As stabilizers there can be used metal salts of fatty acids, such as, for example, magnesium, aluminum and/or zinc stearate or ricinoleate.

Polymers

Suitable cationic polymers are, for example, cationic cellulose derivatives, such as, for example, a quaternized hydroxyethylcellulose which is obtainable under the name Polymer JR 400® from Amerchol, cationic starches, copolymers of diallylammonium salts and acrylamides, quaternized vinylpyrrolidone/vinylimidazole polymers, such as, for example, Luviquat® (BASF), condensation products of polyglycols and amines, quaternized collagen polypeptides, such as, for example, lauryldimonium hydroxypropyl hydrolyzed collagen (Lamequat®L/Grünau), quaternized wheat polypeptides, polyethyleneimine, cationic silicone polymers, such as, for example, amodimethicone, copolymers of adipic acid and dimethylaminohydroxypropyldiethylenetriamine (Cartaretine®/Sandoz), copolymers of acrylic acid with dimethyl-diallylammonium chloride (Merquat® 550/Chemviron), polyaminopolyamides and crosslinked water-soluble polymers thereof, cationic chitin derivatives such as, for example, quaternized chitosan, optionally distributed in microcrystalline form, condensation products of dihaloalkyls, such as, for example, dibromobutane, with bisdialkylamines, such as, for example, bis-dimethylamino-1,3-propane, cationic guar gum, such as, for example, Jaguar® CBS, Jaguar® C-17, Jaguar® C-16 from Celanese, quaternized ammonium salt polymers, such as, for example, Mirapol® A-15, Mirapol® AD-1, Mirapol® AZ-1 from Miranol.

There are suitable as anionic, zwitterionic, amphoteric and non-ionic polymers, for example, vinyl acetate/crotonic acid copolymers, vinylpyrrolidone/vinyl acrylate copolymers, vinyl acetate/butyl maleate/isobornyl acrylate copolymers, methyl vinyl ether/maleic anhydride copolymers and esters thereof, uncrosslinked and polyol-crosslinked polyacrylic acids, acrylamidopropyltrimethylammonium chloride/acrylate copolymers, octylacryl-amide/methyl methacrylate/tert.butylaminoethyl methacrylate/2-hydroxypropyl methacrylate copolymers, polyvinylpyrrolidone, vinylpyrrolidone/vinyl acetate copolymers, vinylpyrrolidone/dimethylaminoethyl methacrylate/vinylcaprolactam terpolymers as well as optionally derivatized cellulose ethers and silicones.

Silicone Compounds

Suitable silicone compounds are, for example, dimethylpolysiloxanes, methylphenylpolysiloxanes, cyclic silicones as well as amino-, fatty acid-, alcohol-, polyether-, epoxy-, fluorine-, glycoside- and/or alkyl-modified silicone compounds, which can be in both liquid and resin-like form at room temperature. Also suitable are simethicones, which are mixtures of dimethicones having an average chain length of from 200 to 300 dimethylsiloxane units and hydrogenated silicates.

Humectants

Humectants serve for further optimizing the sensory properties of the composition as well as for regulating the moisture content of the skin. At the same time, the low-temperature stability of the preparations according to the invention, in particular in the case of emulsions, is increased. The humectants are conventionally present in an amount of from 0.1 to 15% by weight, preferably from 1 to 10% by weight and in particular from 5 to 10% by weight.

There are suitable according to the invention inter alia amino acids, pyrrolidonecarboxylic acid, lactic acid and salts thereof, lactitol, urea and urea derivatives, uric acid, glucosamine, creatinine, cleavage products of collagen, chitosan or chitosan salts/derivatives, and in particular polyols and polyol derivatives (e.g. glycerol, diglycerol, triglycerol, ethylene glycol, propylene glycol, butylene glycol, erythritol, 1,2,6-hexanetriol, polyethylene glycols such as PEG-4, PEG-6, PEG-7, PEG-8, PEG-9, PEG-10, PEG-12, PEG-14, PEG-16, PEG-18, PEG-20), sugars and sugar derivatives (inter alia fructose, glucose, maltose, maltitol, mannitol, inositol, sorbitol, sorbitylsilanediol, sucrose, trehalose, xylose, xylitol, glucuronic acid and salts thereof), ethoxylated sorbitol (sorbeth-6, sorbeth-20, sorbeth-30, sorbeth-40), honey and hardened honey, hardened starch hydrolyzates as well as mixtures of hardened wheat protein and PEG-20-acetate copolymer. Glycerol, diglycerol, triglycerol and butylene glycol are preferably suitable according to the invention as humectants.

Biogenic Active Ingredients and Antioxidants

Biogenic active ingredients are to be understood as being, for example, tocopherol, tocopherol acetate, tocopherol palmitate, ascorbic acid, (deoxy)ribonucleic acid and fragmentation products thereof, β-glucans, retinol, bisabolol, allantoin, phytantriol, panthenol, AHA acids, amino acids, ceramides, pseudoceramides, essential oils, plant extracts, such as, for example, plum extract, Bambara nut extract and vitamin complexes.

Antioxidants interrupt the photochemical reaction chain which is initiated when UV radiation penetrates the skin. Typical examples thereof are amino acids (e.g. glycine, histidine, tyrosine, tryptophan) and derivatives thereof, imidazoles (e.g. urocanic acid) and derivatives thereof, peptides such as D,L-carnosine, D-carnosine, L-carnosine and derivatives thereof (e.g. anserine), carotinoids, carotenes (e.g. α-carotene, β-carotene, lycopine) and derivatives thereof, chlorogenic acid and derivatives thereof, lipoic acid and derivatives thereof (e.g. dihydrolipoic acid), aurothioglucose, propylthiouracil and other thiols (e.g. thioredoxin, glutathione, cysteine, cystine, cystamine and the glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl, y-linoleyl, cholesteryl and glyceryl esters thereof) as well as salts thereof, dilauryl thiodipropionate, distearyl thiodipropionate, thiodipropionic acid and derivatives thereof (esters, ethers, peptides, lipids, nucleotides, nucleosides and salts) as well as sulfoximine compounds (e.g. buthionine sulfoximine, homocysteine sulfoximine, buthionine sulfone, penta-, hexa-, hepta-thionine sulfoximine) in very small tolerable doses (e.g. pmol to μmol/kg), also (metal) chelators (e.g. α-hydroxy fatty acids, palmitic acid, phytic acid, lactoferrin), α-hydroxy acids (e.g. citric acid, lactic acid, malic acid), humic acid, bile acid, bile extracts, bilirubin, biliverdin, EDTA, EGTA and derivatives thereof, unsaturated fatty acids and derivatives thereof (e.g. γ-linolenic acid, linoleic acid, oleic acid), folic acid and derivatives thereof, ubiquinone and ubiquinol and derivatives thereof, vitamin C and derivatives (e.g. ascorbyl palmitate, Mg ascorbyl phosphate, ascorbyl acetate), tocopherols and derivatives (e.g. vitamin E acetate), vitamin A and derivatives (vitamin A palmitate) as well as coniferyl benzoate of benzoin, rutic acid and derivatives thereof, α-glycosylrutin, ferulic acid, furfurylidene glucitol, carnosine, butylhydroxytoluene, butylhydroxyanisole, nordihydroguaiaresin acid, nordihydroguaiaretic acid, trihydroxybutyro-phenone, uric acid and derivatives thereof, mannose and derivatives thereof, superoxide dismutase, zinc and derivatives thereof (e.g. ZnO, ZnSO₄) selenium and derivatives thereof (e.g. selenium methionine), stilbene and derivatives thereof (e.g. stilbene oxide, trans-stilbene oxide) and the derivatives of those mentioned active ingredients that are suitable according to the invention (salts, esters, ethers, sugars, nucleotides, nucleosides, peptides and lipids).

Deodorants and Bacteriostatic Agents

Cosmetic deodorants counteract body odors, mask or eliminate them. Body odors arise due to the action of skin bacteria on apocrine sweat, whereby malodorous degradation products are formed. Deodorants accordingly comprise active ingredients which act as bacteriostatic agents, enzyme inhibitors, odor absorbers or odor-masking agents.

Bacteriostatic agents. There are suitable as bacteriostatic agents in principle any substances which are active against gram-positive bacteria, such as, for example, 4-hydroxybenzoic acid and its salts and esters, N-(4-chlorophenyl)-N′-(3,4-dichlorophenyl)urea, 2,4,4′-trichloro-2′-hydroxy-diphenyl ether (Triclosan), 4-chloro-3,5-dimethyl-phenol, 2,2′-methylene-bis(6-bromo-4-chlorophenol), 3-methyl-4-(1-methylethyl)-phenol, 2-benzyl-4-chlorophenol, 3-(4-chlorophenoxy)-1,2-propanediol, 3-iodo-2-propynylbutylcarbamate, chlorhexidine, 3,4,4′-trichlorocarbanilide (TTC), antibacterial fragrances, thymol, thyme oil, eugenol, clove oil, menthol, mint oil, farnesol, phenoxyethanol, glycerol monocaprate, glycerol monocaprylate, glycerol monolaurate (GML), diglycerol monocaprate (DMC), salicylic acid N-alkylamides such as, for example, salicylic acid n-octylamide or salicylic acid n-decylamide.

Enzyme inhibitors. Esterase inhibitors, for example, are suitable as enzyme inhibitors. They are preferably trialkyl citrates such as trimethyl citrate, tripropyl citrate, triisopropyl citrate, tributyl citrate and in particular triethyl citrate (Hydagen® CAT). The substances inhibit enzyme activity and thereby reduce odor formation. Further substances which come into consideration as esterase inhibitors are sterol sulfates or phosphates, such as, for example, lanosterol, cholesterol, campesterol, stigmasterol and sitosterol sulfate or phosphate, dicarboxylic acids and esters thereof, such as, for example, glutaric acid, glutaric acid monoethyl ester, glutaric acid diethyl ester, adipic acid, adipic acid monoethyl ester, adipic acid diethyl ester, malonic acid and malonic acid diethyl ester, hydroxycarboxylic acids and esters thereof such as, for example, citric acid, malic acid, tartaric acid or tartaric acid diethyl ester, as well as zinc glycinate.

Odor absorbers. There are suitable as odor absorbers substances which are able to absorb and largely retain odor-forming compounds. They lower the partial pressure of the individual components and thus also reduce the rate at which they spread. It is important that perfumes thereby remain unimpaired. Odor absorbers are not effective against bacteria. They comprise as the main constituent, for example, a complex zinc salt of ricinoleic acid or special, largely odor-neutral fragrances, which are known to the person skilled in the art as “fixateurs”, such as, for example, extracts of labdanum or styrax or specific abietic acid derivatives. Odor-masking agents are fragrances or perfume oils which, in addition to their function as odor-masking agents, impart to the deodorants their particular fragrance note. There may be mentioned as perfume oils, for example, mixtures of natural and synthetic fragrances. Natural fragrances are extracts of blossoms, stems and leaves, fruits, fruit skins, roots, woods, herbs and grasses, needles and branches as well as resins and balsams. Animal raw materials are also suitable, such as, for example, civet and castoreum. Typical synthetic fragrance compounds are products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type. Fragrance compounds of the ester type are, for example, benzyl acetate, p-tert.-butyl cyclohexyl acetate, linalyl acetate, phenylethyl acetate, linalyl benzoate, benzyl formate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. The ethers include, for example, benzyl ethyl ether, the aldehydes include, for example, the linear alkanals having from 8 to 18 carbon atoms, citral, citronellal, citronellyl oxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal, the ketones include, for example, the ionones and methyl cedryl ketone, the alcohols include anethol, citronellol, eugenol, isoeugenol, geraniol, linalool, phenylethyl alcohol and terpineol, the hydrocarbons include mainly the terpenes and balsams. Preference is given, however, to the use of mixtures of different fragrances which together produce an appealing fragrance note. Essential oils of relatively low volatility, which are used mostly as flavor components, are also suitable as perfume oils, for example sage oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil, lime blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil, labdanum oil and lavandin oil. Preference is given to the use of bergamot oil, dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol, α-hexyl cinnamaldehyde, geraniol, benzylacetone, cyclamen aldehyde, linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice, lemon oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal, lavandin oil, clary sage oil, β-damascone, geranium oil bourbon, cyclohexyl salicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeine gamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide, romilat, irotyl and floramat, on their own or in mixtures.

Antiperspirants. Antiperspirants reduce perspiration by influencing the activity of the eccrine sweat glands and thus counteract underarm wetness and body odor. Aqueous or water-free formulations of antiperspirants typically comprise the following ingredients:

-   -   astringent active ingredients,     -   oil components,     -   non-ionic emulsifiers,     -   co-emulsifiers,     -   consistency regulators,     -   auxiliary substances such as, for example, thickeners or         complexing agents, and/or     -   non-aqueous solvents such as, for example, ethanol, propylene         glycol and/or glycerol.         There are suitable as astringent antiperspirant active         ingredients primarily salts of aluminum, zirconium or zinc.         Suitable active ingredients having antihidrotic activity of this         type are, for example, aluminum chloride, aluminum         chlorohydrate, aluminum dichlorohydrate, aluminum         sesquichlorohydrate and complex compounds thereof, for example         with 1,2-propylene glycol. Aluminum hydroxyallantoinate,         aluminum chloride tartrate, aluminum-zirconium trichlorohydrate,         aluminum-zirconium tetrachlorohydrate, aluminum-zirconium         pentachlorohydrate and complex compounds thereof, for example         with amino acids such as glycine. Oil-soluble and water-soluble         auxiliary substances conventional in antiperspirants can         additionally be present in lesser amounts. Such oil-soluble         active ingredients can be, for example:     -   anti-inflammatory, skin-protecting or fragrant essential oils,     -   synthetic skin-protecting active ingredients, and/or     -   oil-soluble perfume oils.

Conventional water-soluble additives are, for example, preservatives, water-soluble fragrances, agents for adjusting the pH, for example buffer mixtures, water-soluble thickeners, for example water-soluble natural or synthetic polymers such as, for example, xanthan gum, hydroxyethylcellulose, polyvinylpyrrolidone or high molecular weight polyethylene oxides.

Insect Repellents

There are suitable as insect repellents N,N-diethyl-m-toluamide, 1,2-pentanediol or ethyl butylacetylaminopropionate.

Self-Tanning Agents and Depigmenting Agents

Dihydroxyacetone is suitable as a self-tanning agent. Suitable tyrosine inhibitors, which prevent the formation of melanin and are used in depigmenting agents, are, for example, arbutin, ferulic acid, kojic acid, coumaric acid and ascorbic acid (vitamin C).

Hydrotropes

In order to improve the flow behavior, hydrotropes, such as, for example, ethanol, isopropyl alcohol, or polyols, can also be used; these substances largely correspond to the carriers described at the beginning. Polyols which come into consideration here preferably have from 2 to 15 carbon atoms and at least two hydroxyl groups. The polyols can contain further functional groups, in particular amino groups, or be modified with nitrogen. Typical examples are

-   -   glycerol;     -   alkylene glycols, such as, for example, ethylene glycol,         diethylene glycol, propylene glycol, butylene glycol, hexylene         glycol as well as polyethylene glycols having an average         molecular weight of from 100 to 1000 daltons;     -   commercial oligoglycerol mixtures having an inherent degree of         condensation of from 1.5 to 10 such as, for example, commercial         diglycerol mixtures having a diglycerol content of from 40 to         50% by weight;     -   methylol compounds, such as in particular trimethylolethane,         trimethylolpropane, trimethylolbutane, pentaerythritol and         dipentaerythritol;     -   lower alkyl glucosides, in particular those having from 1 to 8         carbon atoms in the alkyl moiety, such as, for example, methyl         and butyl glucoside;     -   sugar alcohols having from 5 to 12 carbon atoms, such as, for         example, sorbitol or mannitol;     -   sugars having from 5 to 12 carbon atoms, such as, for example,         glucose or sucrose;     -   amino sugars, such as, for example, glucamine;     -   dialcohol amines, such as diethanolamine or         2-amino-1,3-propanediol.

Preservatives

There are suitable as preservatives, for example, phenoxyethanol, formaldehyde solution, parabens, pentanediol or sorbic acid as well as the silver complexes known by the name Surfacine® and the further substance classes listed in Annex 6, Parts A and B of the Kosmetikverordnung (Cosmetics Directive).

Perfume Oils and Flavorings

There may be mentioned as perfume oils mixtures of natural and synthetic fragrances. Natural fragrances are the extracts of blossoms (lily, lavender, rose, jasmine, neroli, ylang-ylang), stems and leaves (geranium, patchouli, petitgrain), fruits (anise, coriander, caraway, juniper), fruit skins (bergamot, lemon, orange), roots (nutmeg, angelica, celery, cardamon, costus, iris, calamus), woods (pinewood, sandalwood, guaiac wood, cedarwood, rosewood), herbs and grasses (tarragon, lemongrass, sage, thyme), needles and branches (spruce, fir, pine, mountain pine), resins and balsams (galbanum, elemi, benzoin, myrrh, olibanum, opoponax). Animal raw materials are also suitable, such as, for example, civet and castoreum. Typical synthetic fragrance compounds are products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type. Fragrance compounds of the ester type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl carbinyl acetate, phenylethyl acetate, linalyl benzoate, benzyl formate, ethylmethyl phenyl glycinate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. The ethers include, for example, benzyl ethyl ether, the aldehydes include, for example, the linear alkanals having from 8 to 18 carbon atoms, citral, citronellal, citronellyl oxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal, the ketones include, for example, the ionones, α-isomethylionone and methyl cedryl ketone, the alcohols include anethol, citronellol, eugenol, isoeugenol, geraniol, linalool, phenylethyl alcohol and terpineol, the hydrocarbons include mainly the terpenes and balsams. Preference is given, however, to the use of mixtures of different fragrances which together produce an appealing fragrance note. Essential oils of relatively low volatility, which are used mostly as flavor components, are also suitable as perfume oils, for example sage oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil, lime blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil, ladanum oil and lavandin oil. Preference is given to the use of bergamot oil, dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol, α-hexyl cinnamaldehyde, geraniol, benzylacetone, cyclamen aldehyde, linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice, lemon oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal, lavandin oil, clary sage oil, β-damascone, geranium oil bourbon, cyclohexyl salicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeine gamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide, romillat, irotyl and floramat, on their own or in mixtures.

There are suitable as flavorings, for example, peppermint oil, spearmint oil, anise oil, star anise oil, caraway oil, eucalyptus oil, fennel oil, lemon oil, wintergreen oil, clove oil, menthol and the like.

Dyes

There can be used as dyes the substances that are suitable and authorized for cosmetic purposes, as are listed, for example, in the publication “Kosmetische Färbemittel” der Farbstoffkommission der Deutschen Forschungsgemeinschaft, Verlag Chemie, Weinheim, 1984, p. 81-106. Examples are Cochineal Red A (C.I. 16255), Patent Blue V (C.I.42051), Indigotine (C.I.73015), Chlorophylline (C.I.75810), Quinoline Yellow (C.I.47005), titanium dioxide (C.I.77891), Indanthrene Blue RS (C.I. 69800) and Madder Lake (C.I.58000). Luminol can also be present as a luminescent dye. These dyes are conventionally used in concentrations of from 0.001 to 0.1% by weight, based on the total mixture.

The total amount of auxiliary substances and additives can be from 1 to 50% by weight, preferably from 5 to 40% by weight, based on the compositions. The preparation of the compositions can be carried out by conventional cold or hot processes; the phase inversion temperature method is preferably followed.

Emulsions

In a preferred embodiment, the emulsions have the following composition:

-   (a) from approximately 0.1 to approximately 20% by weight,     preferably from approximately 1 to approximately 15% by weight and     in particular from approximately 2 to approximately 10% by weight UV     sun protection factors, -   (b) from approximately 0.001 to approximately 2.5% by weight,     preferably from approximately 0.005 to approximately 2% by weight     and in particular from approximately 0.01 to approximately 1.5% by     weight carnosine compounds, -   (c) from approximately 1 to approximately 30% by weight, preferably     from approximately 2 to approximately 25% by weight and in     particular from approximately 5 to approximately 10% by weight     emulsifiers, -   (d) from 0 to approximately 50% by weight, preferably from     approximately 5 to approximately 40% by weight and in particular     from approximately 10 to approximately 20% by weight carriers, and -   (e) from 0 to approximately 50% by weight, preferably from     approximately 5 to approximately 40% by weight and in particular     from approximately 10 to approximately 20% by weight oily     substances,     with the proviso that the indicated amounts, with water and     optionally further auxiliary substances and additives, add up to     100% by weight.

Particular preference is given to emulsions which have the following composition:

-   (a) from approximately 1 to approximately 15% by weight and     preferably from approximately 2 to approximately 10% by weight UV     sun protection factors, -   (b) from approximately 0.005 to approximately 2% by weight,     preferably from approximately 0.01 to approximately 1.5% by weight     and in particular from approximately 0.05 to approximately 0.1% by     weight carnosine compounds, -   (c) from approximately 2 to approximately 25% by weight and     preferably from approximately 5 to approximately 10% by weight     emulsifiers, -   (d) from 5 to approximately 50% by weight, preferably from     approximately 5 to approximately 40% by weight and in particular     from approximately 10 to approximately 20% by weight carriers, and -   (e) from 5 to approximately 50% by weight, preferably from     approximately 5 to approximately 40% by weight and in particular     from approximately 10 to approximately 20% by weight oily     substances,     with the proviso that the indicated amounts, optionally with further     auxiliary substances and additives, add up to 100% by weight.

With regard to the indicated amounts, it is to be noted that they are directed to the person skilled in the art. The person skilled in the art would not consider compositions which either do not add up to or exceed 100% by weight.

Finally, it is pointed out that the invention relates to emulsions that are thermodynamically stable and form spontaneously or with the input of a small amount of mechanical energy. However, it also extends to emulsions which have the same droplet size distribution and have been prepared in a different way, for example by high pressure homogenization. The droplet size diameter can be measured by methods known to the person skilled in the art. Examples of such methods include laser-assisted methods such as, for example, photon correlation spectroscopy, laser diffractometry, laser counting methods or turbidimetry.

INDUSTRIAL APPLICABILITY

The invention further provides a process for the production of sunscreen agents in emulsion form, which process comprises the following steps:

-   (i) providing at least one UV sun protection factor; -   (ii) providing at least one carnosine compound; -   (iii) providing at least one emulsifier; -   (iv) mixing components (a) and (b), optionally with the addition of     carriers, oily substances and/or further cosmetic additives, to form     an emulsion.

Finally, the invention relates also to the use of carnosine compounds of formula (I) as stabilizers for emulsions and in particular emulsions, wherein said compounds are used preferably in amounts in the range from approximately 0.001 to approximately 2.5% by weight—based on the emulsion.

Unless expressly referred to already, the embodiments and preferred ranges mentioned above also apply to the claimed process and the claimed use. Repetition is therefore unnecessary.

The invention will be described in greater detail hereinbelow with reference to implementation examples, but without being limited thereto. The first part contains experimental studies which demonstrate the hitherto unknown character of carnosine compounds as active ingredients for protecting the skin against environmental influences. In the second part, it is shown that carnosines are capable of keeping emulsions comprising UV sun protection factors stable for prolonged periods even at high temperatures. Finally, in the last part, formulation examples are given.

EXAMPLES

Carnosines as Active Ingredients Against Environmental Damage to the Skin

Examples 1 to 6, Comparative Examples C1 and C2

Effectiveness Against Skin Ageing

Background:

The enzyme glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the first step of the so-called “pentose pathway”, in which an important DNA component, namely deoxyribose, is formed. Glucose 6-phosphate (G6P) is thereby converted into 6-phosphogluconate (6PG) by means of G6PDH. At the same time, the coenzyme NADP required thereby is reduced to NADPH2, which in turn is able to catalyze a large number of other biological reactions such as, for example, the recycling of glutathione or lipid synthesis. Reduced glutathione protects many enzymes which have SH groups and cells against oxidative stress, such as, for example, the action of UV. The G6PDH content is thus an important parameter for cell protection and skin renewal.

Method:

G6PDH activity was determined in vitro on human fibroblasts by the enzymatic method of Okada, while the DNA content was determined by the Desaulniers method. The results are summarized in Table 1. The results of 3 series of measurements with triple determination are given in %-rel. compared to a blank sample.

TABLE 1 Stimulation of G6PDH activity (in %-rel.) Conc. DNA G6PDH % after after after after Substance w/v 3 d 6 d 3 d 6 d Blank sample 0 100 100 100 100 C1 Uvinul A 0.001 97 93 88 81 C2 Octocrinyl 0.001 95 90 89 85 1 L-Carnosine 0.001 111 120 105 109 2 Carnitine*HCl 0.001 106 118 104 109 3 L-Carnosine + Uvinul A (1:1) 0.001 119 137 115 120 4 L-Carnosine + Octocrinyl (1:1) 0.001 120 141 116 125 5 L-Carnosine + Uvasorb HEB 0.001 122 138 114 121 (1:5) 6 L-Carnosine + NeoHeliopan 0.001 125 140 110 112 (1:5)

As is shown by the examples, the administration of carnosines has the result that both the amount of cellular DNA and G6PDH increases in a statistically significant manner. This effect, which was already unexpected, can be further increased by combination with UV sun protection filters, although these show no effect at all on their own.

Examples 7 and 8

Inhibition of Apoptosis Induction

Background:

Apoptosis, unlike necrosis, is the natural purposive cell death of specific undesired or damaged cells. It is an active process of the cells (suicide on command). In the case of skin ageing especially, a deficiency of growth factors in the skin leads to induced apoptosis of the skin cells. In the cells affected by apoptosis, the nuclear DNA is degraded by the specific enzyme endonuclease and the DNA fragments are passed into the cytoplasm.

Method:

The ability of carnosines to prevent apoptosis induced by a deficiency of growth factors in human skin cells was studied. These tests were carried out in vitro on human fibroblasts and human keratinocytes. The human cells were cultivated in a nutrient medium (DMEM=Dulbecco minimum essential medium from Life Technologie Sarl) with 10% fetal calf serum (from Dutcher). Bromodeoxyuridine (BrdU) was added to the nutrient medium; it was incorporated into the DNA and later served for detection of the DNA fragments in the cytoplasm. After an incubation period of two days, the nutrient medium was replaced by nutrient medium (DMEM) without fetal calf serum. The active substance to be tested was added. For comparison, a cell sample without active substance to be tested was incubated.

After a further incubation period of one or two days at 37° C., the cells were recovered by trypsinization according to the method of Dunnebacke and Zitcer described in: Cell and tissue culture, Ed.: J. Paul, Churchill Livingstone, 1975, p. 226. After the trypsinization, the cells were centrifuged and counted. Then the content of BrdU in the DNA fragments from the cytoplasm was determined by means of the ELISA test (ELISA kit from Roche). The content of BrdU is a measure of the DNA fragments which have passed from the nucleus, the cell core, into the cytoplasm. The results were based on a million cells and given in percent in comparison to the control. The results are summarized in Table 2 below.

TABLE 2 Number of cells and content of DNA fragments Content of Substance Conc. [% w/v] Cell count DNA fragments Control 0 100 100 7 L-Carnosine 0.001 129 85 8 Carnitine*HCl 0.001 118 88

The in vitro examples show that, by using carnosines, apoptosis in human cell cultures and the content of free DNA fragments in the cytoplasm, and thus the degree of damaged DNA in the nucleus, fall.

Examples 9 and 10

Stimulation of the Synthesis of Dermal Macromolecules (GAG)

Background:

The aim of these tests is to demonstrate a stimulating activity of carnosines on the synthesis of dermal macromolecules on human fibroblast cultures in vitro. The dermis is composed of cells (fibroblasts and mast cells), tissue components (collagen and elastin) and so-called ground substances. These ground substances include, for example, glycosaminoglycan (GAG), hyaluronic acid, chondroitin sulfate, dermatan sulfate and glycoproteins. As a result of skin ageing, the intermolecular strength and elasticity of the dermis, and thus the tautness of the skin, is reduced. Likewise, the number of skin cells present, in particular fibroblasts, is reduced as the skin ages. The collagen fibers are fragmented over time, and the proportion of insoluble to soluble collagen increases. The fine dermal elastic fibers become coarse and are destroyed. The synthesis of GAG (glycosaminoglycan) is reduced. All these processes contribute to skin ageing and the manifestations thereof, such as wrinkles and lack of tautness of the skin.

Method:

The measuring method is based on staining macromolecules in a culture of human fibroblasts which, with type I collagen, forms a collagen gel or collagen lattice fibers. Certain regions of those fibers are quantified by means of staining reagents for the proportion of the mentioned macromolecules.

For that purpose, a suspension of human fibroblasts was mixed with a solution of type I collagen (1-2 mg/ml). This mixture was incubated in a defined nutrient medium (DMEM=Dulbecco minimum essential medium, Life Technologie Sarl) comprising 0.5 or 2% by weight fetal calf serum (FCS) for 14 days at 37° C. in a 5% CO₂ atmosphere in Petri dishes (5 ml per dish) with the addition of different concentrations of the plant extracts to be tested.

The kinetics of the collagen gel concentration was determined 2 to 3 times per week by measuring two perpendicular diameters on each collagen gel using a microscope with an image analysis system. The size of the area is shown in cm² in Table 8. After incubation for 14 days, the density of the collagen gel was determined by image analysis with a light source of visible light, by comparatively analyzing different gray stages. This is a relative determination of the density (0=clear or white and 1=black), which cannot be given a unit.

After an incubation period of 7 and 14 days, biopsies (tissue samples) were taken and histological sections of the collagen gel containing human fibroblasts were obtained. The synthesis of macromolecules was analyzed and quantified by the staining of glycosaminoglycan with PAS Alcian blue, for example from SIGMA, by the periodic acid-Schiff method (PAS) described in: Mowry R W, Anal. NY Adad. Sci. 106 Art 2, 402, 1963. The stimulation of the synthesis of macromolecules was evaluated in the immediate vicinity of fibroblasts. This zone is also referred to as the “perifibroblast area”.

The “perifibroblast” secretion, or the secretion of fibroblasts into the periphery, was quantified by an image analyzer by means of a microscope. Reactive structures in the “perifibroblast area” were detected, and the different gray stages were comparatively determined. The values of the gray stages were thereby subdivided from 0=white to 255=black. These parameters are directly proportional to the intensity of the synthesis of macromolecules and thus to the GAG content of the fibroblasts.

The results of the values of these parameters are shown in Table 3 below and are to be regarded directly as representative values for the synthesis activity of the fibroblasts. The content of GAGs is described as a relative value of the gray stage.

TABLE 3 Content of GAGs in tissue samples of human fibroblasts containing collagen GAG content Area [cm2] Density 14 Substance 7 days 14 days 14 days 7 days days Control* 7.6 4.4 0.35 12.0 10.1 9 0.5% by weight FCS + 10.1 6.0 0.25 12.1 15.1 0.01% by weight L- carnosine 10 0.5% by weight FCS + 9.9 5.8 0.25 11.8 13.3 0.01% by weight carnitine*HCl *5% by weight fetal calf serum (FCS)

The results of the determination of the glycosaminoglycan content in tissue samples of collagen gel containing fibroblasts, especially in the perifibroblast area, show a significant increase in the GAG content as compared with the standard after an incubation period of 14 days with the addition of carnosines. This indicates, in vitro, a regenerating and revitalizing activity of carnosines on human fibroblasts.

Examples 11 and 12

Inhibition of Elastase Activity

Background:

Elastase is a protease which is secreted by the fibroblasts under inflammatory conditions and is jointly responsible for the degradation of dermal macromolecules, such as, for example, collagen and elastin, and thus for skin ageing.

Method:

In order to determine the effectiveness of the plant extract in inhibiting the release of elastase, pancreas elastase (a serine protease) was studied and, as substrate, elastin was labeled with a chromogenic synthetic substrate. The system was incubated with the active ingredients for 30 minutes at room temperature and then, after centrifugation, the optical density of the dye at 410 nm was determined. The amount of extracts used was 0.3% by weight. The results are summarized in Table 4. The results are given relative to a control as standard (=0%); a1-antitrypsin was used as the standard.

TABLE 4 Elastase inhibition Substance Inhibition [%] 11 L-Carnosine 32 12 Carnitine*HCl 28

The results show that carnosines are capable of inhibiting elastase and especially pancreas elastase.

Examples 13 and 14

Inhibition of the Glycation of Collagen

In order to demonstrate that carnosines inhibit the non-enzymatic glycation of macromolecules, type I collagen was treated with glucose and the extracts for a period of 21 days at 45° C. The suspensions were then centrifuged and the content of Schiff's bases in the supernatant liquid was determined by fluorescence measurement at 430 nm. The results are summarized in Table 5. The results are again based on the control as standards (without extract and without glucose).

TABLE 5 Inhibition of the glycation of collagen Substance Inhibition [%] Control without glucose 46 Control with glucose 100 13 L-Carnosine 68 14 Carnitine*HCl 65

The in vitro results indicate that carnosines are capable of inhibiting the glycation of collagen and thus of slowing the ageing process of the dermis by glycation of collagen fibers.

Carnosines as Stabilizers of Emulsions Examples 15 TO 17, Comparative Examples C3 TO C5

Stability Tests

Various emulsions comprising different UV sun protection factors were homogenized under high pressure so that the D50 value was in the range from 0.1 to 100 μm. They were then introduced into 150 ml glasses with lids, with the exclusion of air, and then stored in a drying cabinet for a period of 6 weeks at 40° C. with and without the addition of 0.2% by weight carnosine. Evaluation was made, in each case after storage for 1 week, in accordance with the following scale: (++)=no change; (+)=slight turbidity; (#)=significant turbidity; (−)=separated.

The results are summarized in Table 6. Examples 15 to 17 are according to the invention, while Examples C3 to C5 serve for comparison.

TABLE 6 Stability tests (amounts in % by weight) Composition 15 C3 16 C4 17 C5 Ethylhexyl salicylate 5.0 5.0 5.0 5.0 2.0 2.0 Homosalate 2.0 2.0 — — — — Ethylhexyl methoxycinnamate — — 2.0 2.0 7.0 7.0 Butyl methoxydibenzoylmethane 2.0 2.0 — — — — Homosalate — — 2.0 2.0 — — Phenylbenzimidazole sulfonic acid — — — — 2.0 2.0 Isoamyl p-methoxycinnamate 4.0 4.0 — — — — Octocrylene — — 6.0 6.0 6.0 6.0 4-Methylbenzylidene camphor — — 2.0 2.0 — — Benzophenone-3 — — — — 2.0 Carnosine 0.2 — 0.2 — 0.2 — Polyglyceryl-2 dipolyhydroxystearate 3.0 3.0 3.0 3.0 3.0 3.0 Glyceryl oleate 2.0 2.0 2.0 2.0 2.0 2.0 Cetearyl isononanoate 5.0 5.0 5.0 5.0 5.0 5.0 Dicaprylyl ether 5.0 5.0 5.0 5.0 5.0 5.0 Glycerol 5.0 5.0 5.0 5.0 5.0 5.0 Water Ad 100 Storage stability After 1 week ++ ++ ++ +++ ++ ++ After 2 weeks ++ ++ ++ ++ ++ ++ After 3 weeks ++ + ++ + ++ ++ After 4 weeks ++ + ++ # ++ + After 5 weeks ++ # ++ − ++ # After 6 weeks ++ − + − + −

The emulsions according to the invention are found to be completely stable over 5 weeks when stored at 40° C.; initial clouding occurs after 6 weeks. At that time, all the comparative formulations without added carnosine had already separated.

FORMULATION EXAMPLES

Sunscreen spray (amount in % by weight) Ingredients INCI Amount Water. demineralized Water (aqua) To 100 Glycerol Glycerol 4.00 1.3 butylene glycol Butylene glycol 5.00 Plantacare APG Coco glycosides 2.00 D-Panthenol Panthenol 0.50 Lara Care A-200 Galactoarabinan 0.25 Baysilone oil M 10 Dimethicone 1.00 Edeta BD Disodium EDTA 0.10 Copherol 1250 Tocopheryl acetate 0.50 Cetiol OE Dicaprylyl ether 3.00 Neo Heliopan ® HMS Homosalate 5.00 Neo Heliopan ® AV Ethylhexyl methoxycinnamate 6.00 Neo Heliopan ® 357 Butyl methoxydibenzoylmethane 1.00 Corapan TQ Diethylhexyl naphthalate 2.00 Alpha Bisabolol Bisabolol 0.10 Pemulen TR-2 Acrylates/C10-30 alkyl acrylate 0.25 crosspolymer Carnosine Carnosine 0.01 NaOH. 10% Sodium hydroxide 0.60 Perfume oil Fragrance 0.20 Phenoxyethanol Phenoxyethanol 0.40 Solbrol M Methylparaben 0.10 Solbrol P Propylparaben 0.10 4-hydroxyacetophenone Hydroxyacetophenone 0.50

Sunscreen spray O/W. SPE 15-20 (amount in % by weight) Ingredients INCI Amount Dracorin ® GOC Glyceryl oleate citrate. Caprylic/capric 2.00 triglyceride Corapan ® TQ Diethylhexyl 2.6-naphthalate 3.00 Neo Heliopan ® HMS Homosalate 7.00 Neo Heliopan ® OS Ethylhexyl salicylate 5.00 Neo Heliopan ® 357 Butyl methoxydibenzoylmethane 3.00 Isoadipate Diisopropyl adipate 6.00 Baysilone ® Oil M10 Dimethicone 1.00 Edeta ® BD Disodium EDTA 0.10 Vitamin E Acetate Tocopheryl acetate 0.50 Carnosine Carnosine 0.05 Dragosantol ® 100 Bisabolol 0.10 Pemulen ® TR-2 Acrylates/C10-30 alkyl acrylate crosspolymer 0.25 Water Water (aqua) Ad 100 Glycerol 99.5 P. Glycerol 4.00 Butylene Glycol Butylene glycol 5.00 Neo Heliopan ® Hydro (103089). used Phenylbenzimidazole sulfonic acid 8.00 as 25% aq. solution neutralized with Biotive ® L-Arginine Biotive ® L-Arginine Arginine 0.55 Perfume oil Fragrance 0.40 Sobrol M Methylparaben 0.30 4-hydroxyacetophenone Hydroxyacetophenone 0.60

Sunscreen cream (W/O). SPF 40 (amount in % by weight) Ingredients INCI Amount Dehymuls PGPH Polyglyceryl-2 dipolyhydroxystearate 5.00 Copherol 1250 Tocopheryl acetate 0.50 Permulgin 3220 Ozocerite 0.50 Zinc stearate Zinc stearate 0.50 Tegosoft TN C12-15 Alkyl benzoate 10.00  Neo Heliopan ® Isoamyl p-methoxycinnamate 2.00 E1000 Neo Heliopan ® 303 Octocrylene 5.00 Neo Heliopan ® MBC 4-Methylbenzylidene camphor 3.00 Zinc oxide. neutral Zinc oxide 5.00 Water. distilled Water (aqua) Add 100 EDTA BD Disodium EDTA 0.10 Carnosine Carnosine 0.10 Glycerol Glycerol 4.00 Magnesium sulfate Magnesium sulfate 0.50 Perfume oil Perfume 0.30 Symdiol ® 68 1.2-Hexanediol. Caprylyl glycol 0.30

Sunscreen milk (W/O) (amount in % by weight) Ingredients INCI Amount Dehymuls PGPH Polyglyceryl-2 dipolyhydroxystearate 3.00 Beeswax 8100 Beeswax 1.00 Monomuls 90-0-18 Glyceryl oleate 1.00 Zinc stearate Zinc stearate 1.00 Cetiol SN Cetearyl isononanoate 5.00 Cetiol OE Dicaprylyl ether 5.00 Tegosoft TN C12-15 alkyl benzoate 4.00 Vitamin E Tocopherol 0.50 Neo Heliopan ® OS Ethylhexyl salicylate 5.00 Neo Heliopan ® AV Ethylhexyl methoxycinnamate 7.50 Uvinul ® T150 Ethylhexyl triazone 1.50 Water. distilled Water (aqua) To 100 Trilon BD Disodium EDTA 0.10 Glycerol Glycerol 5.00 Neo Heliopan ® Disodium phenyl dibenzimidazole 15.00  AP 10% solution. tetrasulfonate neutralized with NaOH Perfume oil Perfume 0.25 Alpha bisabolol Bisabolol 0.10 SymOcide ® PT Phenoxyethanol. Tropolone 0.25 Carnosine Carnosine 0.10 

The invention claimed is:
 1. A method for stabilizing an emulsion, comprising adding to the emulsion, a carnosine compound of formula (I)

wherein R1 represents H or CH₃ and R2 represents H or COOH, or salts thereof.
 2. The method as claimed in claim 1, wherein the carnosine compound is used in amounts in the range from approximately 0.001 to approximately 2.5% by weight, based on the emulsion.
 3. The method of claim 1, wherein in addition to the carnosine compound of formula (I), said emulsion further comprises (a) at least one UV sun protection factor, (c) at least one emulsifier, and optionally (d1) a carrier, and/or (d2) an oily substance, with the proviso that the emulsion has a droplet size in which the D50 value is in the range from 0.1 to 100 μm.
 4. The method of claim 1, wherein the emulsion has a droplet size in which the D90 value is in the range from 1 to 150 μm.
 5. The method of claim 1, wherein the emulsion has a droplet size in which both the D50 value and the D90 value are in the range from 0.1 to 100 μm.
 6. The method of claim 1, wherein the compound of formula (I) is selected from the group consisting of carnosine, L-carnosine, D-carnosine, D/L-carnosine, carnitine, carnitine*HCl, anserine, D-anserine, L-anserine and L-anserine*HNO₃ and mixtures thereof.
 7. The method of claim 3, wherein the emulsifier is selected from the group consisting of alkoxylates, alkyl and/or alkenyl oligoglycosides, partial glycerides, sorbitan esters, polyglycerol esters, fatty acids, amphoteric and/or cationic surfactants and mixtures thereof.
 8. The method of claim 3, wherein the carrier is selected from the group consisting of water, alcohols, esters, butylene glycol, dipropylene glycol, ethanol, ethoxydiglycol, ethyl acetate, glycerol, propanol, isopropanol, macrogols, propylpropylene glycol(2) methyl ether, propylpropylene glycol(3) methyl ether, propylene carbonate, propylene glycol, triethylene glycol, isoparaffin, amyl acetate, amyl benzoate, benzyl acetate, butyl acetate, butylene glycol, butyl lactate, butooctyl benzoate, butooctyl salicylate, C₁₀-C₁₃ alkanes, C₁₄-C₁₇ alkanes, C₁₁-C₁₅ cycloalkanes, caprylyl butyrate, isoparaffin, diacetin, triacetin, dicaprylyl ether and dicaprylyl maleate and mixtures thereof.
 9. The method of claim 3, wherein the oily substance is selected from the group consisting of Guerbet alcohols based on fatty alcohols having from 6 to 18 carbon atoms, esters of linear C₆-C₂₂-fatty acids with linear or branched C₆-C₂₂-fatty alcohols or esters of branched C₆-C₁₃-carboxylic acids with linear or branched C₆-C₂₂-fatty alcohols, esters of linear C₆-C₂₂-fatty acids with branched alcohols, esters of C₁₈-C₃₈-alkylhydroxycarboxylic acids with linear or branched C₆-C₂₂-fatty alcohols, esters of linear and/or branched fatty acids with polyhydric alcohols and/or Guerbet alcohols, triglycerides based on C₆-C₁₀-fatty acids, liquid mono-/di-/tri-glyceride mixtures based on C₆-C₁₈-fatty acids, esters of C₆-C₂₂-fatty alcohols and/or Guerbet alcohols with aromatic carboxylic acids, esters of C₂-C₁₂-dicarboxylic acids with linear or branched alcohols having from 1 to 22 carbon atoms or polyols having from 2 to 10 carbon atoms and from 2 to 6 hydroxyl groups, vegetable oils, branched primary alcohols, substituted cyclohexanes, linear and branched C₆-C₂₂-fatty alcohol carbonates, Guerbet carbonates based on fatty alcohols having from 6 to 18, esters of benzoic acid with linear and/or branched C₆-C₂₂-alcohols, linear or branched, symmetrical or unsymmetrical dialkyl ethers having from 6 to 22 carbon atoms per alkyl group, ring-opening products of epoxidized fatty acid esters with polyols, silicone oils, aliphatic or naphthenic hydrocarbons, and mixtures thereof.
 10. The method of claim 3, comprising: (a) from approximately 0.1 to approximately 20% by weight UV sun protection factor, (b) from approximately 0.001 to approximately 2.5% by weight carnosine compound, (c) from approximately 1 to approximately 30% by weight emulsifier, (d) from 0 to approximately 50% by weight carrier, and (e) from 0 to approximately 50% by weight oily substance, with the proviso that the indicated amounts, with water and optionally further auxiliary substances and additives, add up to 100% by weight.
 11. The method of claim 3, comprising: (a) from approximately 0.1 to approximately 20% by weight UV sun protection factor, (b) from approximately 0.001 to approximately 2.5% by weight carnosine compound, (c) from approximately 1 to approximately 30% by weight emulsifier, (d) from approximately 5 to approximately 50% by weight carrier, and (e) from approximately 5 to approximately 50% by weight oily substance, with the proviso that the indicated amounts, optionally with further auxiliary substances and additives, add up to 100% by weight.
 12. The method of claim 3, wherein the UV sun protection factor is selected from the group consisting of organic UV-A and UV-B sun protection factors and mixtures thereof.
 13. The method of claim 12, wherein the UV-A sun protection factor is selected from the group consisting of benzoylmethane and enamine compounds and mixtures thereof.
 14. The method of claim 12, wherein the UV-B sun protection factor is selected from the group consisting of 3-benzylidene camphor and 3-benzylidene norcamphor and derivatives thereof, 4-aminobenzoic acid derivatives, esters of cinnamic acid, esters of salicylic acid, derivatives of benzophenone, esters of benzalmalonic acid, triazine derivatives, propane-1,3-diones, ketotricyclo(5.2.1.0)decane derivatives, 2-phenylbenzimidazole-5-sulfonic acid and salts thereof; sulfonic acid derivatives of benzophenones, sulfonic acid derivatives of 3-benzylidene camphor and mixtures thereof. 